Sensor disposition structure in seat

ABSTRACT

A sensor disposition structure in a seat includes a cushion pad and a board-like member which is disposed under the cushion pad. A concave is formed in an upper surface of the board-like member, and a sensor is disposed in the concave.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Continuation of application Ser. No. 15/855,132 filed Dec. 27,2017, which in turn claims priority to Japanese Patent Application No.2017-147693, filed on Jul. 31, 2017, the entire contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a seat disposition structure in a seat.

2. Description of Related Art

There is a case where a sensor such as a position sensor or the likewhich detects whether a passenger is seated in a seat is disposed in theseat (for example, see JP 2014-100941A).

For example, such sensor is used to detect that a passenger is seated inthe seat in the seatbelt reminder technique where the passenger iswarned when he/she is not wearing the seatbelt although he/she issitting in the seat.

Traditionally, when such sensor is to be disposed in a seat, there is acase where the sensor is to be disposed between the cushion pad and theouter cover of the seat cushion of the seat as described in JP2014-100941A, for example.

However, when a sensor is disposed between a cushion pad and an outercover, that is, if a sensor is disposed right under an outer cover, thesitting comfort may be unpleasant since the passenger who sits in theseat feels something against his/her buttocks and thighs through theouter cover of the seat.

SUMMARY OF THE INVENTION

The present invention is made in view of the above problem and one ofthe objects of the present invention is to provide a sensor dispositionstructure in a seat which can be carried out when disposing a sensor ina seat.

In order to achieve at least one of the objects, according to an aspectof the present invention, there is provided a sensor dispositionstructure in a seat, including: a cushion pad; and a board-like memberwhich is disposed under the cushion pad, wherein a concave is formed inan upper surface of the board-like member, and a sensor is disposed inthe concave.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, advantages and features of the presentinvention will become more fully understood from the detaileddescription given hereinbelow and the appended drawings which are givenby of illustration only, and thus are not intended as a definition ofthe limits of the present invention, and wherein:

FIG. 1 is a schematic view illustrating a seat;

FIG. 2 is a schematic view illustrating an air passage and the likewhich are formed in a cushion pad of a seat cushion;

FIG. 3 is a schematic view illustrating a seat cushion frame and asensor and the like which are disposed in a concave of a pan frame(board-like member);

FIG. 4 is a schematic view illustrating a sensor and an attachmentbracket;

FIG. 5 is an enlarged view illustrating the concave and the like whichare formed in the pan frame (board-like member);

FIG. 6 is a schematic view illustrating a state where the attachmentbracket is attached in the concave;

FIG. 7 is a schematic view illustrating a state where the state shown inFIG. 8 is seen from the back side of the pan frame (board-like member);

FIG. 8 is a schematic view illustrating a state where the attachmentbracket to which the sensor and the like are attached is attached in theconcave;

FIG. 9 is a view illustrating a state where a bracket-side engaging unitwhich is formed at the bent unit of the attachment bracket is engagedwith the lower surface side of the pan frame (board-like member);

FIG. 10 is a cross-sectional view illustrating a state where the sensorwhich is disposed in the concave of the pan frame (board-like member)abuts the lower surface of the cushion pad;

FIG. 11 is a cross-sectional view illustrating a state where the sensoris disposed at the position that is directly under the hollow sectionformed in the cushion pad;

FIG. 12 is a schematic view illustrating an example of a seat cushionframe provided with a wire; and

FIG. 13 is a view illustrating a modification example of the board-likemember or the like which is set so as to have a wire inserted therein.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to the drawings. However, although various technicallypreferred limitations for implementing the present invention areincluded in the following embodiments, the technical scope of thepresent invention is not limited to the following embodiments and theexamples shown in the drawings in any way.

A seat 10 shown in FIG. 1 is placed in a vehicle such as an automobileand the seat 10 is where a passenger such as a driver sits. As shown inFIG. 1, the seat 10 includes a seat cushion 11 which supports thebuttocks and thighs of the passenger, a seat back 14 which becomes abackrest, the lower end section thereof being supported by the seatcushion 11, and a headrest 16 which is provided on the seat back 14 andwhich supports the head of the passenger. Here, auxiliary supportingunits such as a neck-rest, armrests, footrests, an ottoman and the likecan be included in addition.

As shown in FIG. 2, the seat cushion 11 mainly includes a seat cushionframe 17 (see the after-mentioned FIG. 3) which is the bone structure, acushion pad 12 which is disposed on the seat cushion frame 17, and anouter cover 13 (omitted in FIG. 2, see FIG. 1) which forms the outersurface of the seat by covering the seat cushion frame 17 and thecushion pad 12.

In the embodiment, an air passage 30 for air (hot air and cold air) isformed in the seat cushion 11 between the cushion pad 12 and the outercover 13. However, the air passage 30 is not mandatory.

In particular, as shown in FIG. 2, a concave for air passage 30A whichforms a part of the air passage 30 is formed in the cushion pad 12.Further, a concave (not shown) which forms the rest of the air passage30 is formed in the cover member 12A at the position corresponding tothe concave for air passage 30A, and the air passage 30 is formed byfitting the cover member 12A in a predetermined section of the cushionpad 12.

Further, a plurality of punching holes are formed in the cover member12A, and these punching holes are the air vents 30C of the air passage30. Furthermore, the cushion pad 12 including the cover member 12A iscovered with the outer cover 13, at least the section of the outer cover13 corresponding to the air vents 30C being air permeable.

The air taken in from the blower (not shown) is sent inside the airpassage 30 via the through hole 30B, and the air flowed through the airpassage 30 is blown out toward the passenger from the air vents 30C ofthe air passage 30.

The seat cushion 11 of the embodiment includes the seat cushion frame 17under the cushion pad 12. As shown in FIG. 3, the seat cushion frame 17mainly includes side frames 17A which form a left and right pair,connecting members 17B which connect the front end sections and the rearend sections of the side frames 17A (the connecting member 17B for thefront end side is disposed under the pan frame 18), and the pan frame 18which bridges across the side frames 17A and the connecting members 17B.

Here, in the embodiment, a case where the pan frame 18 functions as aboard-like member which is disposed under the cushion pad 12 isdescribed. However, a case where the board-like member is configured ina different form other than the pan frame 18 will be described later asa modification example.

The pan frame 18 (board-like member) has a concave 20 formed in theupper surface thereof, and the sensor 1 is disposed inside the concave20. For example, the sensor 1 can be a position sensor which can detectwhether a passenger is seated in the seat 10.

The sensor 1 can be directly attached in the concave 20. However, in theembodiment, the sensor 1 is fixed to an attachment bracket 2 and then,the attachment bracket 2 to which the sensor 1 is fixed is disposedinside the concave 20.

In the case where the sensor 1 is directly attached in the concave 20 ofthe pan frame 18, the sensor 1 placed in the concave 20 needs to befixated by screwing it thereto and this process can be difficult.However, as described above, by having the configuration where thesensor 1 is fixed to the attachment bracket 2 and then the attachmentbracket 2 is attached in the concave 20, the sensor 1 can be easilyfixed to the attachment bracket 2 and the attachment bracket 2 can alsobe easily attached in the concave 20. Therefore, the sensor 1 can beeasily disposed in the concave 20.

Further, in the state where the seat 10 is assembled, the cushion pad 12is disposed on the sensor 1. Then, when a passenger sits in the seat 10,the load of the passenger is applied to the sensor 1 via the cushion pad12. At this time, if the sensor 1 is directly attached in the concave 20of the pan frame 18, the entire load will be applied to the sensor 1 andthe sensor 1 may be influenced in a bad way. However, if the sensor 1 isattached in the concave 20 via the attachment bracket 2 as describedabove, a part of the load of the passenger will be absorbed by theattachment bracket 2 when the load of the passenger is applied to thesensor 1. Therefore, comparing to the case where the sensor 1 isdirectly attached in the concave 20, the influence of the load of thepassenger on the sensor 1 is reduced.

Hereinafter, the configuration and the like of the concave 20 and theattachment bracket 2 will be described in detail. FIG. 4 is a schematicview illustrating the sensor 1 and the attachment bracket 2, and FIG. 5is an enlarged view illustrating the concave 20 and the like formed inthe pan frame (board-like member).

In the plate-like main body unit 2 a of the attachment bracket 2,engaging holes 2 b with which the engaging units 1 a of the sensor 1engage are formed and holes 2 c in which the screw units 1 b (not shownin FIG. 4, see the after-mentioned FIG. 7) of the sensor 1 are to beinserted are formed. By inserting the engaging units 1 a of the sensor 1in the engaging holes 2 b of the attachment bracket 2 and the engagingunits 1 a respectively engaging with the engaging holes 2 b, and in thisstate, by further screwing on the screw units 1 b which are inserted inthe holes 2 c of the attachment bracket 2 from the back side (that is,the lower side) of the attachment bracket 2, the sensor 1 can be easilyattached to the attachment bracket 2.

A harness 1A which electrically connects the sensor 1 and externaldevices (not shown in the drawing, a power device, a device whichprocesses the signals from the sensor 1 and the like) is connected tothe sensor 1, and the attachment bracket 2 includes a guide unit 2 d forthe harness 1A. Since the guide unit 2 d gradually inclines downwardwith respect to the main body unit 2 a of the attachment bracket 2, theharness 1A is guided by the guide unit 2 d to be in a state where itgradually inclines downward.

If the attachment bracket 2 does not have the guide unit 2 d, theharness 1A will hang down by its own weight at the part where theharness 1A and the sensor 1 are connected. In such state, when thevehicle shakes (e.g. shakes in a vibrating manner) and the seat 10 moves(e.g. moves in a vibrating manner) along with the vehicle shaking, theharness 1A will move (e.g. moves in a vibrating manner) relatively in alarge movement with respect to the sensor 1. Therefore, the harness 1Acan be easily damaged or can be easily cut off. With respect to theabove, by supporting the harness 1A by the guide unit 2 d of theattachment bracket 2 as described above, the harness 1A being in thestate where it gradually inclines downward, the harness 1A which issupported by the guide unit 2 d will not easily move relatively withrespect to the sensor 1 even when the seat 10 moves. Therefore, theharness 1A will not be easily damaged nor easily cut off.

Further, the main body unit 2 a of the attachment bracket 2 has cutouts2 e formed at the outer circumference section thereof.

Due to the attachment bracket 2 having the cutouts 2 e at the outercircumference thereof, even in the case where the sensor 1 and theattachment bracket 2 are in the state of receiving the load as describedabove and a force which can deform the main body unit 2 a of theattachment bracket 2 is applied thereto, the cutouts 2 e absorb thedeformation of the main body unit 2 a of the attachment bracket 2.Therefore, the deformation of the main body unit 2 a of the attachmentbracket 2 can easily return to the original state when the force is notapplied to the attachment bracket 2 any more, and the attachment bracket2 will not remain to be in the deformed state.

On the other hand, the concave 20 of the pan frame 18 has an engagingunit for attaching the attachment bracket 2 in the concave 20 byengaging with the attachment bracket 2 formed thereto.

In particular, as shown in FIG. 5, nail units 20 a are formed as theengaging unit on the upper surface of the concave 20 so as to protrude,the nail units 20 a being formed in the shape of nail. Further, the mainbody unit 2 a of the attachment bracket 2 has engaging holes 2 f whichengage with the nail units 20 a formed therein. When the attachmentbracket 2 to which the sensor 1 is attached is to be attached in theconcave 20, as shown in FIG. 6, the nail units 20 a of the concave 20and the engaging holes 2 f of the attachment bracket 2 will engage witheach other. Here, in FIG. 6, the sensor 1 and the harness 1A are omittedso that the engagement of the nails 20 a and the engaging holes 2 f canbe seen clearly.

As described above, although this can also be said for theafter-mentioned second engaging units 20 b and the like, the attachmentbracket 2 can be easily attached in the concave 20 in the embodimentsince the attachment bracket 2 can be attached in the concave 20 just bymaking the attachment bracket 2 (engaging holes 2 f) engage with theengaging unit (nail units 20 a) formed in the concave 20.

Further, due to the attachment bracket 2 being attached in the concave20 in the state where the nail units 20 a of the concave 20 and theengaging holes 2 f of the attachment bracket 2 engaging with each other,mainly the positioning of the attachment bracket 2 in the front and reardirections can be carried out accurately due to the nail units 20 a.Furthermore, the nail units 20 a can contribute to the positioning ofthe attachment bracket 2 in the right and left directions. Moreover,when the attachment bracket 2 is to be attached to the concave 20, byconfirming that the nail units 20 a protrude upward from the engagingholes 2 f of the attachment bracket 2, whether the engaging holes 2 f ofthe attachment bracket 2 and the nail units 20 a are engaged with eachother in an appropriate way and whether the attachment bracket 2 isdisposed at an appropriate position in the concave can be confirmed.

Here, the case where the sensor 1 is disposed in the concave 20 in thestate where the harness 1A extends to the left side of the sensor 1 isshown in FIGS. 3 to 5. However, there may be a case where the sensor 1is disposed in the concave 20 in the state where the harness 1A extendsto the right side of the sensor 1. Further, the nail units 20 a are onlyformed in the rear side section of the concave 20 in the embodiment asshown in FIG. 5. However, since the direction of the harness 1A, that isthe direction of the guide unit 2 d, may be in the left direction or inthe right direction, therefore, the engaging holes 2 f of the attachmentbracket 2 are formed not only in the rear side section but also in thefront side section as in the state shown in FIG. 4.

Further, as shown in FIG. 5, the second engaging units 20 b are formednear the nail units 20 a on the upper surface of the concave 20. Whenthe attachment bracket 2 is attached in the concave 20, as shown in FIG.6, the edge sections a of the engaging holes 2 f of the attachmentbracket 2 are fit in between the nail units 20 a and the second engagingunits 20 b.

In such way, when the attachment bracket 2 to which the sensor 1 isattached is attached in the concave 20 of the pan frame 18, thepositioning of the attachment bracket 2 in the front and rear directionscan be carried out more accurately due to the edge sections a of theengaging holes 2 f of the attachment bracket 2 being fit in between thenail units 20 a and the second engaging units 20 b of the concave 20.Further, the attachment bracket 2 will not be easily displaced in thefront and rear directions.

Furthermore, in the embodiment, the left and right edge sections of theconcave 20 are formed so as to be slightly higher than the upper surfaceof the concave 20 as shown in FIG. 5, and these sections are the ribs 20c which respectively support the two edge sections (in the embodiment,the left and right sections) of the main body unit 2 a of the attachmentbracket (see FIG. 6).

By having the ribs 20 c in the way as described above, the part of themain body unit 2 a of the attachment bracket 2 other than the partssupported by the ribs 20 c will be slightly in the air, floating abovethe upper surface of the concave 20. Therefore, as described above, theattachment bracket 2 can readily absorb a part of the load when the loadof the passenger is applied to the sensor 1. Moreover, since therigidity of the concave 20 itself can be improved by having the ribs 20c comparing to the case without the ribs 20 c, the concave 20 will notbreak easily when a passenger sits in the seat 1 and the load of thepassenger is applied to the pan frame 18, bending the pan frame 18.

Here, for example, the rigidity of the concave 20 can be improved byfurther forming a rib on the under surface of the concave 20.

Further, escape units 20 d are formed in the concave 20 as openings, andthe escape units 20 d are formed so that the engagement units 1 a, thescrew units 1 b and the like of the sensor which protrude downward fromthe under surface of the attachment bracket 2 can be positioned in theescape units 20 d as shown in FIG. 7 when the attachment bracket 2 isattached to the concave 20. In the embodiment, by having suchconfiguration, the engagement units 1 a, the screw units 1 b and thelike of the sensor 1 which protrude downward from the under surface ofthe attachment bracket 2 will not interfere with the concave 20 when theattachment bracket 2 is attached in the concave 20.

In the embodiment, the attachment bracket 2 also has a structure forengaging with the concave 20 of the pan frame 18. In particular, theattachment bracket 2 includes bent units 2 g which are respectively bentdownward at the left and right edge sections of the main body unit 2 aas shown in FIG. 4. Here, in the state shown in FIG. 4, the left sidebent unit 2 g of the attachment bracket 2 is divided in two, one in thefront side and the other in the rear side, because the guide unit 2 d isformed between the two divided parts of the bent unit 2 g, and the rightside bent unit 2 g of the attachment bracket 2 is formed as oneplate-like unit (see FIG. 7 and the after-mentioned FIG. 9).

When the attachment bracket 2 is to be attached in the concave 20, theribs 20 c of the concave 20 will be tightly fit between the bent units 2g (see FIG. 5) on the left and right sides. In such way, mainly thepositioning of the attachment bracket 2 can be carried out accuratelydue to the bent units 2 g, and the attachment bracket 2 will not beeasily displaced in the left and right directions. Further, by bendingthe attachment bracket 2 to form the bent units 2 g, the rigidity of theattachment bracket 2 itself can be improved.

Further, the bent units 2 g of the attachment bracket 2 havebracket-side engaging units 2 h formed thereto so as to protrude in thefront direction from the front end sections of the bent units 2 g andprotrude in the rear direction from the rear end sections of the bentunits 2 g.

Furthermore, as shown in FIG. 9, when the attachment bracket 2 isattached in the concave 20 of the pan frame 18, the bracket-sideengaging units 2 h of the attachment bracket 2 engage with the undersurface of the pan frame 18 (see β, in FIG. 9, Rs in the drawing showthe ribs formed on the under surface of the pan frame 18). By havingsuch configuration, mainly the positioning of the attachment bracket 2in the upward and downward directions can be carried out accurately dueto the bracket-side engaging units 2 h, and the attachment bracket 2will not be easily displaced in the upward and downward directions.

In the embodiment, as described above, by attaching the attachmentbracket 2 to which the sensor 1 is attached in the concave 20 of the panframe 18, the sensor 1 can be accurately and firmly attached in theconcave 20 of the pan frame 18 via the attachment bracket 2 as shown inFIG. 8.

On the other hand, in the case where the openings 18A are formed in thepan frame 18 as shown in FIGS. 3 and 5, the harness 1A can be guided soas to go under the seat 10 by inserting the harness 1A in an opening18A.

Here, the opening 18A for inserting the harness 1A can be newly formedin the pan frame 18. Hereinafter, although a description will be givenon the basis of FIGS. 3, 5 and other drawings, the present invention isnot limited to the case where two openings 18A are formed as shown inFIG. 3 and other drawings, and there may be one opening 18A or there maybe three or more openings 18A.

Further, there is no need to form the openings 18A on the left and rightsides of the concave 20 as shown in FIG. 3 and other drawings and theopenings 18A may be formed on the front and rear sides or the like ofthe concave 20. Furthermore, the openings 18A may be cutouts (that is,formed in the shapes that are cut out inward from the end sections ofthe pan frame 18), and the openings 18A are not limited to the holes asshown in FIG. 3 and other drawings. Further, the openings 18A do notneed to be the opening for the duct 19 which will be describedhereinafter.

In the seat 10 of the embodiment, as shown in FIG. 2, the air passage 30is formed between the cushion pad 12 and the outer cover 13 of the seatcushion 11. The air sent in from the blower (not shown) which isprovided under the pan frame 18 is sent into the air passage 30 throughthe through hole 30B, and the air flowed through the air passage 30 isblown out toward the passenger from the air vents 30C of the air passage30. Further, an opening 18A is formed as a through hole in which a duct19 (see FIG. 10) for supplying the air to the through hole 30B from theblower can be inserted.

Therefore, by using the opening 18A as the opening for inserting theharness 1A of the sensor 1, the opening 18A for duct which is alreadyformed can be utilized without newly forming an opening 18A in the panframe 18 and the harness 1A can be inserted in the opening 18A.

Moreover, the blower is provided under the pan frame 18 and usually, isprovided either on the left or right side of the seat 10. Therefore, theposition in the pan frame 18 where the duct 19 penetrates is also moreto the left or right with respect to the center corresponding to theposition of the blower. In view of this, in the seat 10 of theembodiment, a total of two openings 18A in which the duct 19 can beinserted are formed, one on the left side and the other on the rightside with respect to the center of the pan frame 18 as shown in FIGS. 3and 5 so as to accommodate both cases.

Further, in the embodiment, the section between the two openings 18A isa concave and the above described concave 20 of the pan frame 18 isformed in this section.

In the embodiment, the openings 18A are formed continuously from theconcave 20 of the pan frame 18 in such way. That is, the above describedconcave 20 in which the sensor 1 and the attachment bracket 2 are to bedisposed is formed at the section between the plurality of openings 18Awhich are formed near each other (the section between the plurality ofopenings 18A that bridges across the front section and the rear sectionof the pan frame 18).

In general, if the plurality of openings 18A are formed near each other,the rigidity of the section between them becomes weak and the sectioncan easily deform. However, in the embodiment, since the rigidity of theconcave 20 itself is improved by having the ribs 20C formed in theconcave 20 which is formed in this section as described above, suchdeformation will not occur easily.

Further, since the harness 1A of the sensor 1 which is attached in theconcave 20 of the pan frame 18 via the attachment bracket 2 is insertedin an opening 18A which is formed continuously from the concave 20, theharness 1A can be easily routed compared to the case where there is adistance between the concave 20 and the opening 18A. Furthermore, ifthere is a distance between the concave 20 and the opening 18A, theharness 1A will be sandwiched between the pan frame 18 and the cushionpad 12 (see FIG. 2 and the after-mentioned FIG. 10) and there is apossibility that the harness 1A is damaged due to the harness 1A and thepan frame 18 or the harness 1A and the cushion pad 12 rubbing againsteach other. However, if the concave 20 and the opening 18A are formedcontinuously as in the embodiment, the rubbing as described above willnot easily occur and the harness 1A will not be easily damaged nor cutoff.

Further, the duct 19 will be inserted in any one opening 18A of theplurality of openings 18A as shown in FIG. 3. Therefore, by insertingthe harness 1A in the opening 18A in which the duct 19 is not inserted,the harness 1A and the duct 19 will not interfere with each other andthe harness 1A and the duct 19 will not rub against each other. Thus,the harness 1A will not be easily damaged nor cut off.

Here, the configuration may be such that the harness 1A is inserted inthe opening 18A in which the duct 19 is inserted.

In the embodiment, the duct 19 is inserted in the opening 18A of the panframe 18 and is inserted in the through hole 30B which is formed in thecushion pad 12 from below as shown in FIG. 10. Since the cushion pad 12will not be raised due to the duct 19 being inserted in the through hole30B, the state where the upper surface of the sensor 1 abutting theunder surface of the cushion pad 12 will be maintained.

Further, when a passenger sits in the seat 10, the load is applied tothe cushion pad 12 from above, the cushion pad 12 is compressed and thepressure applied to the sensor 1 from the cushion pad 12 increases.Therefore, the sensor 1 can reliably detect the load when a passengersits in the seat 10.

Here, in FIG. 10, there is shown a configuration where the upper surfaceof the pan frame 18 and the upper surface of the sensor 1 are in flashand where the cushion pad 12 whose bottom is flat is place on the panframe 18 and the sensor 1. However, the configuration may be such thatthe sensor 1 is disposed so that the upper surface of the sensor 1 behigher than the upper surface of the pan frame 18 and that a concave isformed in the section of the cushion pad 12 corresponding to the sensor1.

Moreover, if the concave 20 of the pan frame 18 is formed at theposition right under a hollow section such as the air passage 30 or thelike formed in the cushion pad 12 as shown in FIG. 11, the section ofthe cushion pad 12 above the hollow section will deform downward andabsorbs the load when a passenger sits in the seat 10, and the load willnot be fully transmitted to the section below the hollow section.Therefore, the pressure applied to the sensor 1 will not increasesufficiently and it may be difficult to detect that a passenger has satin the seat 10 by the sensor 1.

Therefore, it is preferred that the concave 20 in which the sensor 1 isdisposed is formed at a position other than the position right below thehollow section such as the air passage 30 or the like which is formed inthe cushion pad 12. By having such configuration, the load applied tothe cushion pad 12 will be directly applied to the sensor 1 when apassenger sits in the seat 10. Therefore, the pressure which is appliedto the sensor 1 can increase appropriately and whether a passenger hassat in the seat 10 can be easily detected.

As described above, according to the disposition structure of the sensor1 in the seat 10 of the embodiment, the sensor 1 is disposed in theconcave 20 which is formed in the upper surface of the board-like member(pan frame 18) which is disposed under the cushion pad 12 (see FIG. 10).

In the traditional disposition structure of a sensor in a seat, asdescribed above, the sensor 1 is disposed between the cushion pad 12 andthe outer cover 13 (that is, just under the outer cover). Therefore, thepassenger who sat in the seat 10 can feel something against theirbuttocks or thighs through the outer cover 13 of the seat 10 and thesitting comfort may be unpleasant.

However, in the disposition structure of the sensor 1 in the seat 10according to the embodiment, since the cushion pad 12 is placed betweenthe buttocks and thighs of the passenger and the sensor 1 as describedabove, the passenger who is sitting in the seat 10 will not feel thesensor 1 against their buttocks and thighs and the sitting conform ofthe passenger can improve comparing to the traditional case.

Further, if the sensor 1 is simply disposed on the upper surface of theboard-like member (pan frame 18), the cushion pad 12 will be raised forthe height of the sensor 1, and this can cause discomfort in thepassenger who is setting and the sitting comfort may be unpleasant.However, according to the disposition structure of the sensor 1 in theseat 10 of the embodiment, since the concave 20 is formed in the uppersurface of the board-like member (pan frame 18) and the sensor 1 isdisposed therein as described above, such discomfort as described abovecan be avoided and the sitting comfort can be improved.

Further, the sensor 1 is disposed in the concave 20 in a state beingfixed to the attachment bracket 2. Therefore, the sensor 1 can be easilydisposed in the concave 20 since the attachment bracket 2 is attached inthe concave 20 after the sensor 1 is fixed to the attachment bracket 2.Further, when the passenger sits in the seat 10 and the load of thepassenger is applied to the sensor 1 via the cushion pad 12, a part ofthe load will be absorbed by the attachment bracket 2. Thus, comparingto the case where the sensor 1 is directly attached in the concave 20,the influence of the load of the passenger on the sensor 1 becomessmall.

Furthermore, the attachment bracket 2 is attached in the concave 20 in astate being engaged with the engaging unit formed in the concave 20.Therefore, the attachment bracket 2 can be easily attached in theconcave 20. In addition, the positioning of the attachment bracket 2 canbe carried out easily due to the engaging unit, and the attachmentbracket 2 will not be easily displaced in the front and rear directions,in the left and right directions and the like.

Further, the nail unit 20 a which is formed in a nail shape is formed onthe upper surface of the concave 20 as the engaging unit. The nail unit20 a protrudes from the upper surface of the concave 20. Therefore,mainly the positioning of the attachment bracket 2 in the front and reardirections can be carried out accurately. Further, by confirming thatthe nail unit 20 a protrudes upward from the engaging hole 2 f of theattachment bracket 2 when attaching the attachment bracket 2 in theconcave 20, whether the attachment bracket 2 and the nail unit 20 a areengaged properly and whether the attachment bracket 2 is disposed at theappropriate position in the concave 20 can be easily confirmed.

Furthermore, the second engaging unit 20 b is formed on the uppersurface of the concave 20 at a position near the nail unit 20 a.Therefore, when attaching the attachment bracket 2 in the concave 20,the edge section a of the engaging hole 2 f of the attachment bracket 2will be tightly fit between the nail unit 20 a and the second engagingunit 20 b. Thus, the positioning of the attachment bracket 2 in thefront and rear directions can be carried out more accurately and theattachment bracket 2 will not be easily displaced in the front and reardirections.

Further, an opening 18A is formed in the pan frame 18 functions as theboard-like member, the attachment bracket 2 includes the bent unit 2 gwhich is bent at a position corresponding to the opening 18A, and theattachment bracket 2 includes the bracket-side engaging unit 2 h whichprotrudes from an edge section of the bent unit 2 g and which engageswith the under surface of t the pan frame 18. Therefore, mainly thepositioning of the attachment bracket 2 in the left and right directionscan be carried out accurately due to the bent unit, and the attachmentbracket 2 will not be easily displaced in the left and right directions.In addition, the rigidity of the attachment bracket 2 itself can beimproved. Furthermore, since the attachment bracket 2 includes thebracket-side engaging unit 2 h, mainly the positioning of the attachmentbracket 2 in the up and down directions can be carried out accuratelydue to the bracket-side engaging unit 2 h, and the attachment bracket 2will not be easily displaced in the up and down directions.

Furthermore, the attachment bracket 2 is attached in the concave by thebracket-side engaging unit 2 h engaging with the under surface of thepan frame 18 and by the attachment bracket 2 engaging with the nail unit20 a which is formed on the upper surface of the concave 20 so as toprotrude therefrom. Therefore, the positioning of the attachment bracket2 can be carried out more accurately and the attachment bracket 2 willnot be easily displaced in the front and rear directions, the up anddown directions and the like.

Further, ribs 20 c which respectively support the two end sections ofthe attachment bracket 2 are formed on the upper surface of the concave20. Therefore, since the main body unit 2 a of the attachment bracket 2will be in a state slightly floating in the concave 20 with respect tothe part other than the rib parts, the attachment bracket 2 can readilyabsorb a part of the load when the load of the passenger is applied tothe sensor 1. Further, since the rigidity of the concave 20 itself canbe improved by having the ribs 20 c, the concave 20 will not be easilydamaged.

Furthermore, the attachment bracket 2 includes the guide unit 2 d forthe harness 1A which electrically connects the sensor 1 and an externaldevice, and the guide unit 2 d inclines downward. Therefore, the harness1A will be supported by the guide unit 2 d from below in the state wherethe harness 1A gradually inclines downward by being guided by the guideunit 2 d. Thus, the harness 1A which is supported by the guide unit 2 dwill not easily move with respect to the sensor 1 even when the seat 10moves, and the harness 1A will not be easily damaged nor cut off.

Further, the attachment bracket 2 includes the cutout 2 e at an outercircumference section thereof. Therefore, even in the case where theload is applied to the sensor 1 and the attachment bracket 2 and theforce that can deform the attachment bracket 2 is applied, the cutout 2e will absorb the deformation of the attachment bracket 2. Thus, thedeformation of the attachment bracket 2 can easily return to theoriginal state when the force is not applied to the attachment bracket 2any more, and the attachment bracket 2 will not remain to be in thedeformed state.

Furthermore, the opening 18A is formed in the pan frame 18 continuouslyfrom the concave 20, and the harness 1A which electrically connects thesensor 1 and an external device is inserted in the opening 18A.Therefore, the harness 1A can be easily routed comparing to the casewhere there is a distance between the concave 20 and the opening 18A. Inaddition, if there is a distance between the concave 20 and the opening18A, the harness 1A will be placed between the pan frame 18 and thecushion pad 12, and there is a possibility that the harness 1A will bedamaged or cut off due to the harness 1A rubbing against the pan frame18 and the cushion pad 12. However, if the concave 20 and the opening18A are formed continuously, such rubbing against each other will noteasily occur and the harness 1A will not be easily damaged nor cut off.

Further, the duct 19 for supplying air to the air passage 30 which isformed in the cushion pad 12 can be inserted in the opening 18A.Therefore, the opening 18A for the duct 19 which is already formed canbe utilized and the harness 1A can be inserted in the opening 18Awithout forming a new opening in the pan frame 18.

Furthermore, a plurality of openings 18A are formed in the pan frame 18,and the harness 1A is inserted in the opening in which the duct 19 isnot inserted. Therefore, the harness 1A and the duct do not interferewith each other and the harness 1A and the duct 19 do not rub againsteach other. Thus, the harness 1A will not be easily damaged nor cut off.

Further, the concave 20 in which the sensor 1 is disposed is formed at aposition avoiding a position right under the hollow section (e.g. theair passage 30) formed in the cushion pad 12. Therefore, the load whichis applied to the cushion pad 12 when the passenger sits in the seat 10is directly applied to the sensor 1 without being absorbed by the hollowsection formed in the cushion pad 12. Thus, the pressure applied to thesensor 1 can be increased accurately, and it will be easy to detect thatthe passenger has sat in the seat 10 by the sensor 1.

Modification Example

Here, in the above described embodiment, the case where the pan frame 18which is disposed under the cushion pad 12 is used as the board-likemember is described. However, the structure of the seat cushion frame 17under the cushion pad 12 (not shown in FIG. 12), for example, mayinclude the pan frame 18 and the wires 17C (also called S springs or thelike) as shown in FIG. 12 or may only include the wires 17C and not thepan frame 18.

In such case, the board-like member can be set at the section where thewires 17C are disposed.

At that time, for example, the board-like member 25 can be set at thesection where the wires 17C are disposed so that the wires 17C beinserted therein as shown in FIG. 13. Further, in the way similar tothat in the above described embodiment, the concave 26 can be formed inthe upper surface of the board-like member 25 and the sensor 1 can bedisposed in the concave 26 in the state where it is fixated to theattachment bracket 2.

Here, although the engaging units (see FIGS. 4 and 5) and the like forattaching the attachment bracket 2 in the concave 26 are not shown inFIG. 13, the engaging units and the like are formed in both the concave26 and the attachment bracket 2 as needed. Although the harness 1A andthe like of the sensor 1 are also not shown, the attachment bracket 2can also include the guide unit 2 d (see FIG. 4) and the like. Inaddition, the configuration of the concave 20, the attachment bracket 2and the like according to the above described embodiment can be appliedto the concave 26, the attachment bracket 2 and the like of themodification example as needed.

In the case of the modification example shown in FIG. 13, since thewires 17C are inserted in the board-like member 25, the parts of theconcave 26 of the board-like member 25 where the wires 17C are insertedare raised comparing to the other parts (see the dotted lines in thedrawing). Therefore, the cutouts 2 e (see FIG. 4) of the attachmentbracket 2 in the above described embodiment can be formed at thepositions corresponding to the parts raised by the wires 17C which areinserted in the board-like member 25 as shown in FIG. 13.

By having such configuration, in addition to the functions and effectsdescribed in the above embodiment, the attachment bracket 2 and theparts raised by the wires 17C can be prevented from interfering witheach other due to the attachment bracket 2 having the cutouts 2 e formedat the parts corresponding to the parts raised by the wires 17C.Therefore, the attachment bracket 2, the board-like member 25 and thelike can be prevented from being damaged and the like.

Here, it is needless to say that the present invention is not limited tothe above described embodiment and modification example, and variousmodifications can be made as needed as long as they are within the scopeof the invention.

What is claimed is:
 1. A passenger detection sensor, comprising: asensor that detects a load of a passenger; an attachment bracket forattaching the sensor to a seat; wherein the sensor has a substantiallysquare contour in a plan view, the attachment bracket has asubstantially square contour in the plan view, the attachment bracketcomprises engaging holes for fixing the attachment bracket to the seat,and the sensor overlaps with the engaging holes.
 2. The passengerdetection sensor according to claim 1, wherein the engaging holes arearranged along a first side and a second side of the square contour ofthe attachment bracket, the first and second sides being opposite toeach other.
 3. The passenger detection sensor according to claim 1,wherein the attachment bracket further comprises a cutout between theengaging holes, the cutout extending inward.
 4. The passenger detectionsensor according to claim 3, wherein the sensor overlaps with thecutout.
 5. The passenger detection sensor according to claim 1, whereina side of the square contour of the sensor is connected to a harness. 6.The passenger detection sensor according to claim 5, wherein the harnessextends toward a third side of the square contour of the attachmentbracket which is other than first and second sides of the squarecontour, the engaging holes being arranged along the first and secondsides, and the first and second sides being opposite to each other. 7.The passenger detection sensor according to claim 6, wherein theattachment bracket further comprises a bent unit which is bent downwardat each of the third side and a fourth side of the square contour of theattachment bracket, the fourth side being opposite to the third side. 8.The passenger detection sensor according to claim 7, wherein theattachment bracket further comprises a bracket-side engaging unitprotruding laterally from an end of the bent unit.
 9. A vehicle seat,comprising: a seat back; and a seat cushion connected to the seat back,wherein each of the seat back and the seat cushion comprises an innerpad and an outer cover that covers the pad, the seat cushion furthercomprises a pressure receiving member on which the pad is placed, andthe passenger detection sensor according to claim 1 is attached onto thepressure receiving member.